Twin lamp base



FIG. 1 is a top, front and left side perspective view of a twin lampbase showing my new design;

FIG. 2 is a bottom, front and left side perspective view thereof;

FIG. 3 is a left side elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a rear elevation view thereof;

FIG. 6 is front elevation view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken line showing of the environment is for illustrative purposesonly and forms no part of the claimed design.

The ornamental design for a twin lamp base, as shown and described.